The present invention relates to a vehicular navigation system and method that provides a guidance of a recommended vehicle travel route to a destination, and more particularly to a system and method that provides guidance of intersections on the recommended vehicle travel route.
Various vehicular navigation systems are proposed and used to provide a recommended vehicle travel route to a destination, thereby navigating vehicle drivers to the destination. Some of the navigation systems also provide guidance of intersections which appear on the travel route. Such guidance include voice guidance which indicates name of the intersection, distance to the intersection, direction of turn at the intersection, or the like.
This guidance of intersection is provided only for intersections which are more likely to cause drivers to leave the recommended travel route without the guidance. These intersections are determined by checking a road relation between a road entering the intersection and roads exiting from the intersection. The road relation may be defined based on road classes (e.g., national, prefectural, city), angles of crossing, or the like. However, this intersection determination sometimes does not match the sense of drivers.
It is an object of the present invention to provide a vehicular navigation system and method that makes a road relation determination matching a sense of drivers.
It is another object of the present invention to provide a vehicular navigation system and method which makes a road relation determination based on the number of lanes of a road and, when necessary, provides a lane guidance in addition to intersection guidance.
According to the present invention, a vehicular navigation system has a control unit that determines and provides a recommended travel route. The control unit checks for the number of each road branching from an entering road of the travel route at an intersection when the entering road has a plurality of traffic lanes. If an exiting road of the travel route from the intersection has a largest number of traffic lanes among the branching roads, no intersection guidance is provided. If the exiting road has a smaller number of traffic lanes, an intersection guidance is provided. This intersection guidance may include guidance of turn direction and guidance of traffic lane to be taken.